Field of the Invention
Portable grinding tools are customarily hand-held units and for this reason have limited torque and speed capability necessitated by the maximum weight that can conveniently be held in an operator's hands. A recent patent, U.S. Pat. No. 3,214,869, discloses a portable grinding apparatus in which the motor is mounted within a wheeled canister and connected through a flexible shaft to a hand-held grinding tool. While this structure is an improvement over the prior devices in that drive motors of higher torque and speed capability can be used than used in previous hand-held tools, the device is still limited since the canister-housed motor is cumbersome and limits freedom of movement of the operator.